I am seldom surprised at the stories I hear about love and intimacy after covering the subject for more than three decades. Yet in my 150 interviews with women ages 20 through 90 for my new book, I did get socked with a few surprises. Topping that list were the similarities I found in the romances of single women in their twenties and single women in their seventies, and beyond: They share the thrill of discovering new relationships. They share a desire for sex to turn into emotional commitment. They share fears about STDs. And both young and older women share a profound interest in sexual pleasure.

“In this growing field of Sexuality and Aging we are seeing many myths being shattered, particularly the myth of the little old lady who doesn’t want to be sexual after menopause,” Dr. Melanie Davis told me. Davis is A Certified Sexuality educator and co-founder of the New Jersey Center for Sexual Wellness.

“If you had great sex before you turned 50 odds are you can still have great sex after the age of 50. This is a time when couples may be with new partners and having oral sex for the first time, using sex toys for the first time – it really can be a very satisfying time a person’s sexual life,” she says.

Indeed, as many steamy stories as I gathered from women in their twenties, there were ones that were just as hot from women with arthritis and hysterectomies. They are merrily tackling the last lap of life with longer life spans, and increased health and vigor.

Many of these widows had been with the same partners their whole adult lives, and the complaint that sex goes from great to boring to non-existent was one I heard often. Some of those women had spent the last several years nursing sick husbands. And while the loss of a spouse causes intense grief there was also a sense of emancipation. This feeling was evident in an interview I conducted with an 80-year-old recent widow, newly in love with a widower her age “who makes me feel like a teenager.”

Her husband had his first heart attack at the age of 38 and lived with a chronic coronary condition. Then came throat cancer, and in his final months he was stricken with leukemia. As his health deteriorated she became more of a loving caregiver than a lover: “Are you kidding? Sex? It would have killed him,” his widow says with a husky laugh. “After taking care of someone for some many years discovering someone new, it’s just fantastic. The love, the making love — this is exciting beyond exciting.

That ebullience over a new relationship as “exciting beyond exciting” was mirrored in some of the voices I heard of recent college graduates. They had moved out of the cloying friends-with-benefits scene, in which a group of friends party in a cluster and interchange partners. There is little exclusivity or couples-dating. Transiting into the professional world they are now enjoying a new, and more mature, stable of material.

“After four years at the same college, the friend circle I hung out with got very tight, and very incestuous,” said a 22-year-old editorial assistant at a big city magazine, “In college you hook up with boys. Now, after work in the bars, you are meeting real men. I am having the first serious relationship of my life, which means I am actually seeing the guy for more than three months straight.

“We’ll see how long it lasts,” she added with a sigh. “I am ready to become emotionally involved with someone. I’m always afraid the guy just wants sex.”

Older women expressed the same fears — that while good sex is always a bonus, what they want most of all is an emotional connection. Viagra has pumped new vigor into aging men, and as one 73-year-old widow new to the dating world reported to me, many of the old guys are “not thinking with their minds and hearts … they are obsessed with their re-energized organs.”

“These older men who are dancing in the streets because of Viagra often miss out on the most important part of a woman’s sexual pleasure, and that is being touched in the right way, and being held, and adored,” said Dr. Marilyn Charwat, a sex therapist based in Boca Rotan, Fla., told me.

Both young and old alike share another challenge in an era when any new lover has likely had lots of old lovers. The rampant spread of STDs are no longer solely a plague of the youth. Widows and older divorcees, eager for a renewal of sexual activity, are increasingly being exposed to sexual diseases.

I spoke to Maryland therapist Marge Coffey, whose practice is largely single women, about how to broach the subject with a new romantic prospect. She offered this wise and frank advice: “When you are ready to sleep with a new partner, have him or her get tested for everything.”

In the five years from 2005 to 2009, the number of reported cases of syphilis and Chlamydia among those 55 and older increased 43 percent, according to an Orlando Sentinel analysis of data provided by the Centers for Disease Control and Prevention. In Riverside County, California, home of the retirement mecca of Palm Springs, reported cases were up 50 percent over the five-year span, according to data from that county’s health department.

“We used to worry that our grandkids weren’t having safe sex,” said a 73-year-old Miami woman. “Now I make any new boyfriend show me his medical reports. And when it comes up clean I’m eager to try out a new partner. Who knows? That man just might be The One.”